The use of an underwire as part of a brassiere frame has become common. The underwire, of metal, plastic-coated metal or plastic generally is received in a tubular pocket below each cup and lies along the sternum of the wearer substantially at the junction of the breast with the chest wall. Each cup is provided with such an underwire which maintains the configuration of the cup and contributes the support of the breast.
In the past, problems have been encountered with such underwires. For example some underwire designs tended to poke through the fabric or to shift in the fabric pocket which was provided.
The pull on the underwire when the brassiere is fastened, because of the tension applied around the back of the wearer, tended to spread the underwire which generally had a U or C shape.
Frequently the stiffness of the underwire rendered the brassiere uncomfortable and often the lack of ability of the underwire to deform out of its plane caused discomfort as well. When efforts were made in the past to make the underwire more flexible, it tended to lose its stabilizing function.
Furthermore, techniques for inserting the underwire, anchoring the underwire or generally assembling an underwire to the cup and other structures of the brassiere made fabrication complex and expensive. In particular, the tension on the underwire when the brassiere was tightened around the back of the wearer could not be counteracted in the past except by making the wiring so stiff that its breast-shaping and supporting function was defeated.
An effort to overcome at least some of these disadvantages is found in U.S. Pat. No. 6,447,365 which describes a brassiere which ultimately was found to be impractical because of the stiffness of the armature embedded in the softer surround.